For getting started, here are some notes on
emulation/debugging controls, BIOS files, and ROM-Image formats for NSS
and SFC-Box cartridges.
Details on new features: complete release notes
for all versions.

Hardware Donations
If you've some old SNES hardware that you want to get rid off, and that you
want to donate for emulation and research purposes, some things that I am
looking for would be:

Naki/Fire Tribal tap (five-player adaptor, the thing has 5 connectors, but only 4 seem to be working)

A snes mouse (for testing it's sensitivity/threshold)

BSX-Flashcart (mini-flashcart for BSX games)

Nintendo Power-Flashcart (big-flashcart with unknown access protocol)

Photos of different Hudson (and third-party) Multitap PCBs (don't need to have the real hardware, but would be nice to see what is in there).

Aside from SNES hardware, some other stuff that I am currently looking for: